WASHINGTON, November 13, 2025 — The United States has approved a potential Foreign Military Sale of AIM-9X Block II Sidewinder tactical missiles to the Government of Denmark, with an estimated value of $318.4 million. The Defense Security Cooperation Agency delivered the required certification to Congress, enabling the proposed sale to proceed.
Denmark has requested up to 340 AIM-9X Block II missiles along with 34 tactical guidance units. The package also includes non-military items such as training aids, weapon software, support equipment, spare and repair parts, technical documentation, transportation, and both U.S. Government and contractor engineering and logistics services. Officials said the sale will improve Denmark’s ability to address current and future threats while maintaining interoperability with U.S. and NATO forces.
The AIM-9X Block II represents the most advanced variant of the Sidewinder family. It uses a high-resolution Imaging Infrared (IIR) guidance system that allows high off-boresight targeting and enhances resistance to modern infrared countermeasures. Exceptional maneuverability is achieved through conventional control surfaces combined with a thrust vector control system, enabling the missile to engage targets even outside the launch aircraft’s line of sight.
Powered by a solid-fuel Mk 36 rocket motor, the missile can reach speeds exceeding Mach 2.5. It measures approximately 3.02 meters in length, 12.7 centimeters in diameter, and weighs around 85 kilograms. The 9.4-kilogram Annular Blast Fragmentation warhead detonates via proximity fuze, with an effective engagement range between 20 and 35 kilometers.
The Block II variant adds a datalink feature that supports Lock-On After Launch (LOAL), allowing pilots to launch the missile and update targeting information in flight. This capability is crucial for aircraft such as the F-35, which carry weapons in internal bays. The missile also integrates with helmet-mounted cueing systems to allow pilots to lock on simply by looking at the target.
RTX Corporation of Arlington, Virginia, will serve as the principal contractor. Four U.S. Government and four contractor personnel will temporarily deploy to Denmark to provide technical oversight and program support. The sale is not expected to affect the basic military balance in the region or reduce U.S. defense readiness.
Denmark currently operates the AIM-9X system with its F-35A aircraft and ground-based air defense units, and officials stated that the country can readily integrate the missiles and associated support services into its existing defense infrastructure. The U.S. Department of State emphasized that the sale will strengthen the security of a NATO ally and support broader U.S. foreign policy objectives in Europe.
